Bar codes are becoming ubiquitous in our society and especially for use in medical settings. This is increasingly so as there has been a general movement to more carefully monitor the identity of patients and correlate to each patient the various kinds of medications/treatments he receives and other aspects of his stay/treatment/etc. Some of this is being mandated by the passage of new laws requiring more discipline in these matters, and some of it is being adopted out of the desire to be able to more carefully ensure that each patient receives the proper care and treatment, and is billed for it appropriately. This is true in all kinds of medical environments, including in-patient care, out-patient care, emergency room care, pediatric care, nursing home care, mental health care, and virtually all other instances where accurate patient identification is needed.
One of the co-inventors herein has been active in this area, and has invented numerous inventions that have been patented as an aid in identifying patients and correlating them with the various accoutrements of their status as a patient. See for example, U.S. Pat. Nos. 5,933,993; 6,000,160; 6,067,739; 6,438,881; 6,510,634; 6,748,687; 7,017,293; 7,017,294; and 7,047,682, the disclosures of which are incorporated herein by reference. Various of these disclosures are for wristbands and associated labels of various constructions which can be conveniently prepared at the same time and individually printed with identifying indicia, such as bar codes, for rapid and simple electronic reading with a wand or scanner for inputting patient data as well as data relating to any other desired information. For example, the labels may be removed from the form and used to identify blood or other tissue samples, medical charts, and even mundane items such as utensils, etc. for patients suffering from infectious or communicable diseases.
As used herein, the term bar code is defined as any machine readable (typically through electro-optical processes) indicia, marking, symbol or a patterned or ordered arrangement of any such items which represents or contains data which is coded into the arrangement, layout, or other pattern thereof and readable at least by an electronic data entry device. Another common example of character reading other than strict bar code reading that is intended to be included by the inventors as falling within the concept of their invention is optical character reading. A bar code may also be decipherable without machine aid as well to ascertain the data contained therein, and such status does not exclude it from being considered as a bar code. A bar code may be applied to a surface through any of many means such as laser printing or the like.
Reading and obtaining a successful input of the data contained in a bar code is not a simple matter. Standards have been set for this concept of “scannability” which relates to the probability of obtaining an accurate scan at a given distance between a bar code reader and a bar code. See, for example, ANSI INCITS 182 as well as ANSI verification guideline X3.182-1990 Annex A. The greater the probability of obtaining a scan at a greater distance is indicative of a higher scannability. As bar codes are printed on wristbands, for example, and other surfaces which might not necessarily be exactly flat, and the reader may not be always aligned perfectly with the bar code or at the optimum reading angle, or the ambient light may not be ideal, and the printing of any bar code is necessarily subject to variations caused by the variations imparted by the printing process itself, an increased scannability is very important in ensuring that bar codes are accurately read, especially in a medical setting, as described above.
Still another reason that scannability is important relates to the particular environment in many health care settings. When a patient is resident in a medical facility, and it is nighttime or in any other low ambient light environment, the care givers have difficulty in reading bar coded information from a patient's wristband or otherwise at nighttime or in any other low ambient light environment. A care giver would prefer not to turn on the lights and awake the patient, or might alternatively use a flashlight, but the absence of proper lighting creates problems in scanning the bar code. First of all, the caregiver must locate the patient's wrist where the wristband is located, but also the wristband is not presented in a reliably flat orientation meaning that bar code scannability becomes more important to obtaining an accurate read. While the co-inventor's prior inventions have helped immensely by presenting these bar codes in a large, sharply laser-printed font on a bright white face sheet background, either on the wristband or the accompanying labels, the scannability of the bar code itself still introduces the possibility of an error in acquiring or scanning the data. This is further impacted by the added workload and aging population of caregivers, along with the increased complexity of the care provided, resulting in more required patient interaction and increased numbers of times that a patient's ID must be verified, both day and night. Hence, there is a real need in this environment for a bar code with improved scannability. Some prior art attempts to improve scannability may be found in U.S. Pat. Nos. 4,575,625; 5,080,456; and 5,107,100, the disclosures of which are incorporated herein by reference.
Improving contrast can help to compensate for the real world factors that tend to diminish scannability such as poor print quality on the bar code or the bar code design itself. Poor print quality results from, for example, a thermal transfer printer that has not been serviced properly, or that uses the wrong ink ribbon for the surface being printed, or is run at the wrong temperature settings-any of which may result in bar codes with gaps, thin spots where not enough ink has deposited, ragged edges, and areas where ink flows outside the area where it is supposed to be. Alternatively, bar code design factors to consider include bar codes with high density and low wide-to-narrow bar ratios which are more challenging to scan and read. These factors as well as the ordinary real world manufacturing tolerances inherent in printing a bar code onto a surface, as well as the real world inaccuracies inherent in a “read” attempt made “in the field” wherever that might be and the circumstances surrounding that “read” attempt place an increased emphasis on an improved scannability rating of a bar code under test conditions.
Others have attempted to improve scannability of a bar code through use of fluorescent or phosphorescent ink, but these prior art attempts have centered on utilizing such inks for printing of the bar codes themselves. One such effort is found in U.S. Pat. No. 6,303,929, the disclosure of which is incorporated herein by reference. Another prior art patent (U.S. Pat. No. 4,724,309) has been found that makes use of such inks as a background, but the reference teaches that the ink may be used to mark specific zones of a bank draft for example where a user may enter handwritten or typed indicia that may then be optically read in blackout conditions by passing the bank draft under ultraviolet light. The location of the area is identified by the placement of the ink, and although the reference suggests that improved readability for optical scanning is achieved, the reference teaches that bar codes may be placed on the bank draft but not in one of these zones. Furthermore, the reference teaches that such a bar code could optimally be imprinted in the very same fluorescent or phosphorescent ink, much like the '929 patent. Thus, while others have sought to improve bar code scannability through the use of these kinds of inks, the prior art has met with limited success.
The inventors are also aware of fluorescent inks being used to coat labels for other purposes, some of which may accept bar codes. For example, one such popular category of label is marketed under the Dayglo™ trademark. These labels are generally coated with a bright, even garish, color fluorescent ink such as fuscia or lime green to draw an observer's eye to it and cause it to be noticed. One popular use of such labels may be found in supermarkets where price specials are marked on these labels and they then are placed amongst the shelves for the shopper to see as they scan the shelves looking for their food items to purchase. Other labels are coated with other kinds of fluorescent ink, such as the ones generally considered to fall in the category of “invisible” ink meaning that the coating is not viewable by the naked eye except under a special light, such as an ultraviolet light. These labels also may have been imprinted with bar codes and used in the prior art.
While these labels are expected to be found in the prior art, the inventors are now not aware that anyone has determined that coating a label with fluorescing ink before imprinting a bar code on it will improve its scannability.
In attempting to solve the problem presented by trying to scan bar code imprinted wristbands, which inherently are difficult to read for the reasons given above, the inventors have for the first time determined that applying a fluorescing ink coating to an underlying substrate dramatically improves its scannability. Instead of printing the bar code itself in fluorescing ink, the method of choice as taught in the prior art for improving bar code scannability, the inventors have conceived of overcoating a patch or area of a print surface with the fluorescing ink instead and then printing the bar code directly onto it, such as with laser printing. This has been found to dramatically improve the scannability of bar codes printed onto the overcoated surface compared to an uncoated surface in virtually any level of ambient light and with virtually any bar code pattern. One key factor impacting scannability is the contrast ratio that can be obtained between the bar code and its background. The ideal has been believed to be obtained with a flat black bar code bar that adsorbs 100% of the light from the scanner printed on a bright white opaque surface that reflects 100% of the light. This ideal is impossible to achieve in the real world for reflecting light situations, for one reason that no reflective surface will reflect 100% of the light impacting it, but contrast ratios approaching 90% can be achieved. However, adding in the fluorescence feature dramatically improves the reflective light real world results and although the inventors haven't tested it scientifically, it is believed that using the present invention of fluorescent ink produces results approaching ideal. In testing, utilizing this fluorescent ink overcoat background has been found to add to this contrast ratio, as well as result in dramatically improved scannability ratings as reported below. This occurs when the fluorescent ink is energized by shorter wavelength “invisible” light in the 300 to 400 nanometer range thus emitting longer wavelength visible light in the 400 to 700 nanometer range, which can be better “seen” by the naked eye and the bar code reader by intensifying the contrast of the background to the black bar code. While not completely scientifically investigated or understood, the inventors believe it is the “fluorescing effect” of the coating that provides the dramatic improvement in scannability. Fluorescent inks do much more than merely reflect as they actually emit energy (radiation) in the form of visible light when energized by another light source (a bar code scanner) which emits a broad spectrum of light waves including UV in the 300 to 400 nanometer range needed to fluoresce the ink coating. In essence, a combination of the reflection from the white substrate plus the visible light emitting from the fluorescent ink amplifies the contrast of the black bars to the supercharged white background.
The fluorescent ink used may be any of a range of inks, such as UV curable, water based and solvent based fluorescent inks and coatings, with the important consideration being its ability to increase the intensity of light returning from the background surface over that of an uncoated surface or a surface which does not exhibit a fluorescing or similar effect. As used herein, the term “fluorescing” or “fluorescent” ink may be understood to include all such inks, including luminescent inks as well.
In an alternative embodiment, the inventors conceive of a paper stock layer made from a mix of materials such that the finished surface exhibits the reflective qualities similar to that of the layered coating of fluorescent ink of the first embodiment. In this embodiment, instead of an overcoating or layering of ink, which would require a separate additional step in manufacture, the inventors contemplate that the mixture of materials prepared in formulating the face stock during its manufacture would have added to it the appropriate materials as would be known to those of skill in the art to produce a face stock having a finished surface exhibiting the same desired fluorescing properties. The inventors are aware of brighteners, for example, that are routinely added to face stock mixtures which increase the brightness of the finished surface of the face stock, and contemplate that a similar such process could be used to achieve the purposes of the present invention. With this alternative embodiment, it is anticipated that fewer manufacturing steps would be needed.
An overview of the invention has been provided herein. Further details of the invention may be learned by referring to the drawings and description of the preferred embodiment which follow.